M&M NonCardiac Monitoring Flashcards
(119 cards)
Mandatory monitor for any anesthetic, including moderate sedation, no contraindications
pulse oximetry
Where is the pulse ox sensor applied?
A sensor with a light source and detector is placed across the tissue, that can be transilluminated.
Oxygenated hgb absorbs more
Infrared light (940nm)
Deoxygenated hgb absorbs more
RED light (660 nm)
What is the basis of oximetric determinations?
Change in light absorption
How does the pulse oximetry?
Microprocessor analyzes the ration of red to infrared absorptions. to provide O2 saturation.
Pulse ox , arterial pulsations, identified by
Plethysmography, allows for correction for absorption by nonpulsative venous blood and tissue.
Clinically detectable cyanosis requires
5 g of desaturated hgb and corresponds to an SPO2 of less than 80%
Usually goes undetected by pulse ox in the absence of lung disease or low FiO2
Bronchial intubation
Methemoglobin has the
Same absorption coefficient at both red and infrared wavelengths.
Red and infrared with methemoglobin absorps in what ratio?
1:1
1:1 absorption ration seen with methemoglobin corresponds to a saturation reading of
85%
Things causes pulse ox artifact.
Methylene blue dye
low perfusion
malpositioned sensor
leakage of light from the light emiting diode to the sensor.
What is required to obtain mixed venous blood oxygen saturation
Pulmonary artery catheter with fiberoptic sensor to determine SvO2
Noninvasive brain oximetry
monitors regional O2 saturation of Hg in the brain.
In contrast to pulse ox, brain oximetry measures
Venous
Capillary
Arterial saturation
thereby providing oxygen saturation of all regional hemoglboin
What can dramatic decrease regional oxygen saturation (rSO2)
Cardiac arrest
Cerebral embolization
Deep hyothermia
Severe hypoxia
Capnographs rely on the absorpition of
Infrared light by CO2
Capnography: Nondiverting (mainstream)
Measure Co2 passing through an adpator placed in the breathing circuit.
Capnography: Diverting (aspiration)
Continously suction gas from the circuit into a sample cell in the monitor.
Capnography: Diverting (aspiration): HIGH ASPIRATION rates
defined as up to 250ml/min and low dead-space sampling tubing usualy increase SENSITIVITY and decrease lag time.
Capnography: Diverting (aspiration): Low ASPIRATION rates
50ml/min can underestimated ETCO2 during rapid ventilation.
Capnography : diverting (sidestream) units are prone to
Water precipitation that can cause obstruction of the sampling line and erroneous readings.
How is expiratory valve malfunction determined
Detected by the presence of CO2 in inspired gas.